Reduced pressure augmentation of microfracture procedures for cartilage repair

ABSTRACT

A system for applying a treatment to a defect in one bone of two bones forming a joint that comprises a bladder for delivering a reduced pressure to the defect and for providing a positive pressure as bracing between the two bones of the joint is disclosed. A method for applying such treatment is also disclosed. A bladder for applying such treatment that comprises a reduced-pressure chamber and a bracing chamber is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/141,593, filed Dec. 30, 2008, which is hereby incorporated byreference.

BACKGROUND

1. Field of the Invention

The present application relates generally to tissue treatment systemsand in particular to treatment of articular cartilage undergoingmicrofracture procedure.

2. Description of Related Art

Clinical studies and practice have shown that providing a reducedpressure in proximity to a tissue site augments and accelerates thegrowth of new tissue at the tissue site. The applications of thisphenomenon are numerous, but application of reduced pressure has beenparticularly successful in treating wounds. This treatment provides anumber of benefits, including faster healing and increased formulationof granulation tissue. Typically, reduced pressure is applied to tissuethrough a porous pad or other manifolding device. The porous padcontains cells or pores that are capable of distributing reducedpressure to the tissue and channeling fluids that are drawn from thetissue. The porous pad often is incorporated into a dressing havingother components that facilitate treatment.

Articular cartilage is a highly organized avascular tissue composed ofchondrocytes formed in an extracellular matrix. This tissue is extremelyimportant to the normal, healthy function and articulation of joints.Articular cartilage enables joint motion surfaces to articulate smoothlywith a very low coefficient of friction. It also acts as a cushion toabsorb compressive, tensile, and shearing forces and, thus, helpsprotect the ends of bone and surrounding tissue.

Age, injury and wear, and cartilage disorders, such as osteoarthritis,affect millions of people throughout the world. Traumatic chondralinjuries, for example, are common in sports and other activities thatcause severe stress and strain to joints. Osteoarthritis is also acommon condition that develops as cartilage wears, weakens, anddeteriorates at the joint motion surfaces of bones. Indeed, it iscurrently believed that 85% of all Americans will develop degenerativejoint disease as a result of normal activities that damage articularcartilage.

Articular cartilage is generally thin with an extremely low orinsignificant blood flow and, as such, has a very limited ability torepair or heal itself Partial-thickness chondral defects, for example,cannot spontaneously heal. If these defects are left untreated, theyoften degenerate at the articular surface and progress toosteoarthritis. Full-thickness defects that penetrate subchondral bonecan undergo some spontaneous repair if fibrocartilage forms at thedefect. Even in spite of the formation of fibrocartilage, clinicalevidence shows that full-thickness defects continue to degenerate andprogress to osteoarthritis if these defects are left untreated.

Early diagnosis and treatment are crucial to hindering or stopping theprogression of arthritis and degeneration of articular cartilage atjoint motion surfaces. Today, depending on the grade of chondral damage,patients usually have several surgical options to repair or regeneratearticular cartilage. Some current techniques to repair cartilage includeimplantation of chondrocytes, implantation of synthetic matrices andsurgical intervention, with reattachment and reconstruction of thedamaged tissue. None of these methods are totally satisfactory and theyrarely restore full function or return the tissue to its native normalstate. In addition, none of these methods are proven to regeneratecartilage in situ and in vivo.

Micro-fracture surgery is one treatment modality used to treat cartilagedefects. This technique is a marrow-stimulating arthroscopic procedureto penetrate the subchondral bone to induce fibrin clot formation andthe migration of primitive stem cells from the bone marrow into thedefective cartilage location. Generally, the base of the defective areais shaved or scraped to induce bleeding. An arthroscopic awl or pick isthen used to make small holes or microfractures in the subchondral boneplate. The end of the awl is manually struck with a mallet to form theholes while care is made not to penetrate too deeply and damage thesubchondral plate. The holes penetrate a vascularisation zone andstimulate the formation of a fibrin clot containing pluripotential stemcells. The clot fills the defect and matures into fibrocartilage.

While microfracture surgery has a high success rate, patients cannotreturn to sports or other intense activities for about 4 months, evenwith the help of physical therapy. Additionally, the tissue that formsin the defect is primarily fibrocartilage (this constitutes a repairprocess whereby a different tissue type is formed), which does not havethe same functional characteristics of articular (hyaline) cartilage. Assuch, there is currently an acute need for a method that leads to moreof a regenerative response (forms the same type of tissue that wasdamages, for example, hyaline cartilage) rather than a repair responseand that reduces the overall time of healing.

It would therefore be advantageous to provide devices, methods andsystems to promote healing and/or tissue regeneration aftermicrofracture surgery. Such devices, methods and systems would decreasehealing time, and lead to better functional outcomes thus increasing thepatient's quality of life and enable a more rapid return to normal dailyactivities.

SUMMARY

The problems presented by existing methods for microfracture surgery aresolved by the systems and methods of the illustrative embodimentsdescribed herein. These systems and methods are designed to deliverreduced pressure to the joint space where microfracture surgery isperformed. Traditional reduced pressure delivery methods to a jointspace, in particular a knee joint, would apply reduced pressure to theentire joint. The systems and methods described herein concentrateapplication of the reduced pressure on the defect (e.g., the site of themicrofracture surgery) by utilizing a bladder having a reduced-pressurechamber with an opening that surrounds the defect to avoid applyingreduced pressure to the entire joint.

In one embodiment, a system for applying a treatment to a defect in afirst bone of two bones forming a joint is disclosed and comprises areduced-pressure source for providing a reduced pressure, apositive-pressure source for providing a positive pressure, and abladder. The bladder is formed with a reduced-pressure chamber in fluidcommunication with the reduced-pressure source and a bracing chamber influid communication with the positive-pressure source. Thereduced-pressure chamber and bracing chamber both have walls formed froma flexible material, and the reduced-pressure chamber has an openingsized to substantially surround the defect in the first bone. A portionof the walls of each of the reduced-pressure chamber and the bracingchamber form an interior wall of the bladder.

The system further comprises a manifold positioned within thereduced-pressure chamber between the interior wall and the opening inthe reduced-pressure chamber and formed of a porous material fordistributing reduced pressure and providing structural support betweenthe first bone and contact portion of the interior wall. When positivepressure is applied to the bracing chamber, the walls of the bracingchamber inflate to provide bracing between the interior wall and asecond bone of the two bones. When reduced pressure is applied to thereduced-pressure chamber, the walls of the reduced-pressure collapsetoward the interior wall causing the manifold to provide a seal with thecontact portion of the interior wall against the defect and providebracing between the contact portion of the interior wall and the firstbone.

In another embodiment, a method for applying the treatment is alsodisclosed and first comprises performing surgery on the defect in thefirst bone. The method then comprises positioning a reduced-pressurechamber in the joint adjacent the defect, positioning a bracing chamberin the joint between the reduced-pressure chamber and a second bone ofthe two bones, and positioning a manifold within the reduced-pressurechamber adjacent the defect and the bracing chamber. The method furthercomprises applying a positive pressure to the bracing chamber to forcethe manifold against the first bone to brace the reduced-pressurechamber against a second bone of the two bones and then applying areduced-pressure to the defect through a hole in the reduced-pressurechamber and the manifold,

In a further embodiment, a method is provided that includes performingmicrofracture surgery to a knee. The method comprises creating at leastone microfracture in a bone at the base of an articular cartilage defectin the knee, then applying reduced pressure to the site of the defect.

Other objects, features, and advantages of the illustrative embodimentswill become apparent with reference to the drawings and detaileddescription that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic, cross-sectional view of a reduced-pressuretreatment system for repairing cartilage in a knee joint that includes afluidic system, a bladder positioned between the femur and tibia of theknee joint, and a first embodiment of a manifold structure within thebladder;

FIG. 1B is a schematic, perspective view of the bladder and femur shownin FIG. 1A;

FIGS. 2A and 2B are schematic, cross-sectional views of the bladdershown in FIG. 1A with and without reduced pressure being applied to thebladder;

FIG. 2C is a schematic, perspective view of the bladder shown in FIG. 1Awithout reduced pressure and flattened to be rolled as shown in FIG. 7B;

FIG. 3 is a schematic, cross-sectional view of the bladder shown in FIG.1A including a second embodiment of a manifold structure;

FIG. 4 is a schematic, cross-sectional view of the bladder shown in FIG.1A including scaffold material;

FIG. 5 is a schematic, cross-sectional view of the bladder shown in FIG.1A including a barrier material;

FIG. 6 is a schematic view of a fluid control system for the fluidicsystem shown in FIG. 1A;

FIG. 7A is a schematic, perspective view of the bladder shown in FIG.1A,

FIG. 7B is a perspective view of the bladder after being rolled orfolded, and FIG. 7C is a perspective view of the rolled bladder insertedwithin a delivery catheter;

FIG. 8 is a schematic, cross-sectional view of the delivery catheter androlled bladder of FIG. 7C inserted into the knee joint;

FIG. 9 is a schematic, cross-sectional side view of another embodimentof a bladder similar to the bladder shown in FIG. 1A; and

FIGS. 10A and 10B include a perspective and plan views, respectively, ofthe bladder shown in FIG. 1A including an elongated tab.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following detailed description of the illustrative embodiments,reference is made to the accompanying drawings that form a part hereof.These embodiments are described in sufficient detail to enable thoseskilled in the art to practice the invention, and it is understood thatother embodiments may be utilized and that logical structural,mechanical, electrical, and chemical changes may be made withoutdeparting from the spirit or scope of the invention. To avoid detail notnecessary to enable those skilled in the art to practice the embodimentsdescribed herein, the description may omit certain information known tothose skilled in the art. The following detailed description is,therefore, not to be taken in a limiting sense, and the scope of theillustrative embodiments are defined only by the appended claims.

Referring to FIGS. 1A and 1B, a reduced pressure therapy system 100 forapplying reduced pressure and facilitating the growth of tissue at atissue site in the body of a patient such as, for example, the kneejoint in a leg 101 of the patient comprising the femur 102 and tibia103. Any portion of the knee joint may have developed a defect thatneeds repair, for example, a defect 104 in the articular cartilage ofthe lateral condyle of the femur 102. The defect 104 may also be amicro-fracture surgery site as described above where it is desired toregenerate, repair, add or promote growth of new cartilage tissue or anytissue functioning as a structure and support of the body including,without limitation, areola connective tissue, dense connective tissueand cartilage.

The reduced pressure therapy system 100 also comprises a reducedpressure source 115 for providing a reduced pressure to a bladder 105comprising a reduced-pressure chamber 106 and a bracing chamber 107divided by an interior wall 108 within the bladder 105. It should beunderstood that the chambers 106,107 may be separate chambers withoutthe common interior wall 108. The bladder 105 is positioned between thebones 102, 103 with the reduced-pressure chamber 106 positioned adjacentthe femur 102. It should be understood that the defect 104 could also bein the tibia 103 with the reduced-pressure chamber 106 positionedadjacent such defect in the tibia 103. The reduced pressure source 115is fluidly coupled to the reduced-pressure chamber 106 of the bladder105 via a first conduit 110. The reduced pressure therapy system 100further comprises a canister 113 fluidly coupled between the reducedpressure source 115 and the reduced pressure chamber 106 of the bladder105 to collect bodily fluids, such as blood or exudate, that are drawnfrom the femur 102 via the defect 104. In one embodiment thereduced-pressure source 115 and the canister 113 are integrated into asingle housing structure.

In the context of this specification, the term “reduced pressure”generally refers to a pressure that is less than the ambient pressure ata tissue site that is subjected to treatment. In most cases, thisreduced pressure will be less than the atmospheric pressure of thelocation at which the patient is located. Although the terms “vacuum”and “negative pressure” may be used to describe the pressure applied tothe tissue site, the actual pressure applied to the tissue site may besignificantly greater than the pressure normally associated with acomplete vacuum. Consistent with this nomenclature, an increase inreduced pressure or vacuum pressure refers to a relative reduction ofabsolute pressure, while a decrease in reduced pressure or vacuumpressure refers to a relative increase of absolute pressure.

The system 100 further comprises a first fluid supply 111 that isfluidly coupled to the bracing chamber 107 of the bladder 105 via asecond conduit 112. The first fluid supply 111 provides a bracingsubstance to the bracing chamber 107 via the second conduit 112 to fillthe bracing chamber 107 under a positive pressure so that the bracingchamber 107 expands and exerts a positive force on the tibia 103 andsurrounding tissue as well as the interior wall 108 of the bladder 105.The positive pressure applied to the bracing substance in the bracingchamber 107 is sufficient to allow the bracing chamber 107 to conform tothe shape and contours of the tibia 103 and surrounding tissue whilesimultaneously providing a cushion between the femur 102 and the tibia103 without collapsing. It is to be understood that the bracing chamber107 of the bladder 105 may comprise multiple chambers to achieve thedesired cushioning and conformance with the tibia 103 and surroundingtissue. The bracing substance may be a gas or a liquid such as, forexample, a highly viscous compressible material such as a putty, slurry,or colloid.

Both the first conduit 110 and the second conduit 112 may be coupled tothe bladder 105 via connectors 114 and 116, respectively. Both conduits110, 112 may be coated with an anti-coagulant to prevent a build-up ofbodily fluids or blood within the conduits. As used herein, the term“coupled” includes direct coupling or indirect coupling via a separateobject. The term “coupled” also encompasses two or more components thatare continuous with one another by virtue of each of the componentsformed from the same piece of material. Also, the term “coupled” mayinclude chemical, mechanical, thermal, or electrical coupling. Fluidcoupling means that fluid is in communication between the designatedparts or locations.

The bladder 105 is shown with and without a reduced pressure applied tothe reduced-pressure chamber 106 in FIGS. 2B and 2A, respectively.Referring more specifically to FIG. 2A, the bladder 105 comprises twoexterior walls including a reduced-pressure exterior wall 126 whichforms the external surface of the reduced-pressure chamber 106 andbracing exterior wall 127 which forms the external wall of the bracingchamber 107. The reduced-pressure exterior wall 126 has a generallycircular opening 128 which is shaped to fit the perimeter of the defect104. The bladder 105 further comprises a manifold structure 120 that maybe two separate manifold components 120 a, 120 b positioned on bothsides of the defect 104 in the femur 102 as shown in FIG. 1A or that maybe substantially cylindrical in shape with an inner diameter that isconcentrically aligned with the opening 128 of the reduced-pressureexterior wall 126 as shown in FIG. 1B. The upper surface of the manifoldstructure 120 may be sealed against the inside surface of thereduced-pressure exterior wall 126. The manifold structure 120 may havea height somewhat less than the distance between the reduced-pressureexterior wall 126 and the interior wall 108 so that it is slightlysuspended over the interior wall 108 when the reduced-pressure chamber106 is not under pressure.

When a reduced pressure is applied to the reduced-pressure chamber 106as shown in FIG. 2B, the reduced-pressure exterior wall 126 collapses tothe position shown as 126′ with the manifold structure 120 being forcedagainst the interior wall 108 and forming a seal with a portion of theinterior wall 108 to concentrate the reduced pressure on the defect 104.The portion of the interior wall 108 defined by the inner diameter ofthe manifold structure 120 may form a slightly dimpled portion 108′ as aresult of the reduced pressure being applied through the manifoldstructure 120. The dimpled portion 108′ of the interior wall 108 and theinner surface 129 of the manifold structure 120 define a cavity 130 thatis positioned adjacent the defect 104. Consequently, thereduced-pressure exterior wall 126 provides a seal around the defect 104for applying the reduced pressure directly to the defect 104 via theopening 128 in the reduced-pressure exterior wall 126. The manifoldstructure 120 also serves to prevent the exterior wall 126 fromcollapsing against the interior wall 108, allowing the reduced pressureto continue to be applied to the defect 104 in the femur 102. Themanifold structure 120, whether a single piece or multiple manifoldcomponents 120 a and 120 b, is selected to provide adequate structuralsupport within the reduced-pressure chamber 106 between the femur 102and the interior wall 108 while still functioning within thereduced-pressure chamber 106 as forming a part of the cavity 130.

The interior wall 108 is substantially impermeable to block thetransmission of fluids including both liquids and gases. The interiorwall 108 may be a single layer of material or multiple layers ofmaterial depending on the manufacturing process of the bladder 105.Although the manifold structure 120 may form a slight dimpled portion108′ as a result of the reduced pressure being applied to the reducedpressure chamber 106 and the positive pressure being applied to thebracing chamber 107, the interior wall 108 is substantially inflexibleto reduce the amount of bending or flexing in response to the pressuresbeing applied on both sides. Such materials may include, for example,fiberglass, metals, rubbers, or plastics alone or in combination. Theinterior wall 108 must be sufficiently inflexible or rigid to ensurethat the cavity 130 does not collapse against the defect 104 when thereduced pressure and bracing pressure are applied to the bladder 105.

The exterior walls 126, 127 are also fabricated from an impermeablematerial to substantially block the transmission of fluids.Additionally, the exterior walls 126, 127 must be sufficiently thick towithstand the tensile stress and compressive stress created by theapplication of the reduced pressure to the reduced-pressure chamber 106and the positive pressure to the bracing chamber 107, respectively.Consequently, the exterior walls 126, 127 may be formed of multiplelayers of material having the same or different properties. For example,the exterior walls 126, 127 may have a first layer that is impermeableto fluids and second layer that has sufficient flexibility andstructural support when under pressure. These characteristics are ofcourse dependent upon the specific materials used to fabricate theexterior walls 126, 127 of the bladder 105.

The material used to form the exterior walls 126, 127 may contain one ormore elastomers so that they have rubber-like properties. For example,in some embodiments, the flexible material has elongation rates greaterthan 100% and a significant amount of resilience. The resilience of amaterial refers to the material's ability to recover from an elasticdeformation. Examples of elastomers include, but are not limited to,natural rubbers, polyisoprene, stryrene butadiene rubber, chloroprenerubber, polybutadiene, nitrile rubber, butyl rubber, ethylene propylenerubber, ethylene propylene diene monomer, chlorosulfonated polyethylene,polysulfide rubber, polyurethane, and silicones. Elastomers may alsoinclude, but are not limited to, polyurethane elastomers, includingelastomers based on both aromatic and aliphatic isocyanates; flexiblepolyolefins, including flexible polyethylene and polypropylenehomopolymers and copolymers; styrenic thermoplastic elastomers;polyamide elastomers; polyamide-ether elastomers; ester-ether orester-ester elastomers; flexible ionomers; thermoplastic vulcanizates;flexible poly(vinyl chloride) homopolymers and copolymers; flexibleacrylic polymers; and blends and alloys of these, such as poly(vinylchloride) alloys like poly(vinyl chloride)-polyurethane alloys. Theexterior walls 126, 127 may also include, but are not limited to,polyester-polyurethanes, polyether-polyurethanes, andpolycarbonate-polyurethanes. The different elastomeric materialsdescribed above may be combined as lends to form the exterior walls 126,127 in one layer, or alternatively, may be formed as separate layers.The exterior walls 126, 127 may be formed of bioinert materials, i.e.,materials which do not elicit a strong immunological reaction againstthe material and are not toxic, but which do not degrade within the bodyover time.

The manifold structure 120 distributes the reduced pressure within thereduced-pressure chamber 106 to the defect 104 while providing supportas a spacer between the interior wall 108 and the reduced-pressureexterior wall 126 in the collapsed position 126′ as shown in FIG. 2B.When the reduced-pressure exterior wall 126 is forced against the femur102, the reduced pressure is applied directly to the defect 104 via thecavity 130 which includes the manifold structure 120 that continues todistribute the reduced pressure to the defect 104. The manifoldstructure 120 comprises an open-cell foam material that includes aplurality of cells fluidly coupled to each other to form a plurality offlow channels within the manifold structure 120. The cells and flowchannels may be of uniform shape and size or may include a pattern orrandom variations to more precisely direct the flow of fluids throughthe flow channels within the manifold structure 120.

In one illustrative embodiment, the manifold structure 120 is a foammaterial that may be either hydrophobic or hydrophilic. In onenon-limiting example, the manifold structure 120 is an open-cell,reticulated polyurethane foam such as GranuFoam® dressing available fromKinetic Concepts, Inc. of San Antonio, Tex. In the example in which themanifold structure 120 is made from a hydrophilic material, the manifoldstructure 120 also functions to wick fluid out of the cavity 130, whilecontinuing to provide reduced pressure to the defect 104 as a manifold.The wicking properties of the manifold structure 120 draw fluid awayfrom the defect 104 by capillary flow or other wicking mechanisms. Anexample of a hydrophilic foam is a polyvinyl alcohol, open-cell foamsuch as V.A.C. WhiteFoam® dressing available from Kinetic Concepts, Inc.of San Antonio, Tex. Other hydrophilic foams may include those made frompolyether. Other foams that may exhibit hydrophilic characteristicsinclude hydrophobic foams that have been treated or coated to providehydrophilicity.

In another embodiment, the manifold structure 120 may be constructedfrom bioresorbable materials that do not have to be removed from apatient's body after the defect 104 has been repaired and thereduced-pressure chamber 106 fully collapses. Suitable bioresorbablematerials may include, without limitation, a polymeric blend ofpolylactic acid (PLA) and polyglycolic acid (PGA). The polymeric blendmay also include, without limitation, polycarbonates, polyfumarates, andcapralactones. The manifold structure 120 may further serve as ascaffold for new cell-growth, or a scaffold material may be used inconjunction with the manifold structure 120 to promote cell-growth. Ascaffold is a substance or structure used to enhance or promote thegrowth of cells or formation of tissue, such as a three-dimensionalporous structure that provides a template for cell growth. Illustrativeexamples of scaffold materials include synthetic, biosynthetic, andbiologic material such as calcium phosphate, collagen, PLA/PGA, coralhydroxy apatites, carbonates, autologous tissue, or processed allograftor xenograft materials.

The manifold structure 120 may also include a closed-cell material toprovide sufficient support within the reduced-pressure chamber 106 toprevent the exterior wall 126 collapsing prematurely on the interiorwall 108. The closed-cell material also contains a plurality of cells,but the majority of these cells are not fluidly coupled to each otherwith flow channels so that they provide a more solid structural supportwithin the reduced-pressure chamber 106. The closed-cell material issufficiently dense to maintain the three-dimensional shape of themanifold structure 120 to provide structural support within thereduced-pressure chamber 106 and to prevent the open-cells fromcollapsing and cutting off the flow of reduced pressure through the flowchannels.

Consequently, the size of the cells in the manifold structure 120 mustbe sufficiently large to facilitate the communication of fluids throughthe plurality of cells in the manifold structure 120, but sufficientlysmall with lower porosities to provide structural support within thereduced-pressure chamber 106. While the size of the cells in themanifold structure 120 is not exactly known, it is between about 100microns at the low end to maintain sufficient permeability allowing airand fluids to move therethrough when under pressure, and about 1500microns on the high end to maintain sufficient structural support forthe femur 102. Further, the size and number of cells in the manifoldstructure 120 affect the porosity of the manifold structure 120. In oneembodiment, the porosity percentage should be at least about 50% toensure that the manifold structure 120 continues to facilitate fluidflow through the open-cell structure. The porosity percentage should beno greater than about 85% to ensure that the manifold structure providessufficient structural support. Thus, the porosity of the manifoldstructure 120 should be in a range of about 50% to about 85%.

Referring again to FIGS. 1A, 1B, and 2B, the interior wall 108 issufficiently rigid to prevent the dimpled portion 108′ of the interiorwall 108 and the inner diameter surface 129 of the manifold structure120 from contacting the defect 104. Material may be positioned withinthe cavity 130 adjacent the defect 104 that promotes healing of thedefect 104, or provides additional structural support, or provides abarrier to isolate the reduced-pressure chamber 106 from the defect 104,or all the foregoing. For example, additional manifold material may beplaced within the cavity 130 to provide additional structural support ina similar fashion as the manifold structure 120 described above, and/orto function as scaffold material to promote healing of the defect 104. Amanifold structure may also function as a scaffold material to promotehealing of the defect 104. Such a manifold structure may bebioresorbable and left in place after the reduced pressure deliverysystem 100 is removed.

The shape of the manifold structure 120 may be any that prevents theexterior wall 126 from collapsing against the interior wall 108 withinthe reduced-pressure chamber 106 when being subjected to a reducedpressure. Thus, the manifold structure 120 may support only a portion ofthe exterior wall 126 of the reduced-pressure chamber 106 as illustratedin FIG. 2A. Alternatively, a manifold structure 320 may fill most of thereduced-pressure chamber 106 to support the entire inner portion of theexterior wall 126 of the reduced-pressure chamber 106 as shown in FIG.3. When a reduced pressure is applied to the reduced-pressure chamber106, the reduced-pressure exterior wall 126 does not collapse to theposition shown as 126′ as shown in FIG. 2B. However, the manifoldstructure 320 is still forced against the interior wall 108 to form thecavity 130 positioned adjacent the defect 104. Consequently, thereduced-pressure exterior wall 126 provides a seal around the defect 104for applying the reduced pressure directly to the defect 104 via theopening 128 in the reduced-pressure exterior wall 126 as shown in FIG.2B. This particular embodiment provides more structural support to thereduced-pressure chamber 106 of the bladder 105 if, for example, moresupport is needed for the femur 102 as preferred in some embodiments.

The manifold structure 320 may also include a portion that functions asscaffold material to promote healing of the defect 104. The scaffoldportion may be sized to fill a defect that is a gap or void in the femur102 and may be a separate or integrated component of the manifoldstructure 320. The scaffold portion of the manifold structure 320 may bebioresorbable and left in place after reduced-pressure delivery system10 is removed. Referring more specifically to FIG. 4, such a manifoldstructure 420 is shown that includes a scaffold component 422 to promoteregeneration of the defect 104 while at the same time providingadditional structural support between the femur 102 and the interiorwall 108 of the bladder 105. The manifold structure 420 may beconstructed of similar foam material as the manifold structure 120 asdescribed above. The scaffold component 422 comprises primarilyopen-cell material to facilitate fluid communication between themanifold structure 420 and the defect 104. As such, the scaffoldcomponent 422 serves as an additional manifold to more efficientlydistribute reduced pressure across the entire surface of the defect 104,while at the same time providing some cushion between the femur 102 andthe interior wall 108 of the bladder 105. The scaffold component 422 ofthe manifold structure 420 may be coated or infused with growth factors,cells or nutrients to promote the growth of cells and/or theregeneration of cartilage tissue. The scaffold component 422 may also beself-seeded whereby the reduced pressure pulls cells from thesurrounding bone or other body tissues into the cells of the scaffoldcomponent 422 where they may grow and/or form new tissue. Further, thescaffold component 422 may be seeded with cells ex vivo, prior toapplication.

The size of the cells in the scaffold component 422 must be sufficientlylarge to maintain fluid flow through the plurality of cells in thestructure, but sufficiently small with lower porosities to provideenough structural support within the scaffold component 422 to ensurethat the flow channels therein do not collapse significantly and thescaffold component 422 retains its shape to function as a scaffold whena reduced pressure is applied to the reduced-pressure chamber 106. Thescaffold component 422 in a reduced pressure environment may have theopen cell structure that collapses to about 10%, about 20%, about 40%,about 80%, or any range therebetween to avoid disrupting orsignificantly altering fluid communication within the scaffold component422. The cell size and porosity of the scaffold component would be inthe same range as described above for the manifold structure 120.

The scaffold component 422 may be constructed as a separate componentthat contacts a surface of the manifold structure 120 with a looseinterface that allows the scaffold component 422 to separate easily fromthe manifold structure 120 when the bladder 105 is removed from thefemur 102. Thus, the scaffold component 422 remains in place at the siteof the repaired defect 104 when the bladder 105 is removed.Alternatively, the scaffold component 422 may be constructed so that itadheres to the surface of the manifold structure 120 using, for example,an adhesive that causes the scaffold component 422 to remain attached tothe manifold structure 120 when the bladder 105 removed from the femur102. Thus, the scaffold component 422 does not remain in place at thesite of the repaired defect 104 when the bladder 105 is removed. Whenthe scaffold component 422 is intended to be removed with the manifoldstructure 420, they may be fabricated as a unitary component (not shown)with dual porosities such that they function in the same manner asdescribed above. Such unitary components with dual porosities aredisclosed and described in U.S. Pat. No. 6,695,823 and InternationalApplication No. PCT/US2008/000596 (International Publication No. WO2008/091521 A2), both of which are hereby incorporated by referenceherein.

The scaffold component 422 may be constructed from materials includingsynthetics, biosynthetics, or biologics such as calcium phosphate,collagen, PLA/PGA, coral hydroxy apatites, carbonates, autologoustissue, or processed allograft or xenograft materials. The scaffoldcomponent 422 may also be formed of bioinert materials, i.e., materialswhich do not elicit a strong immunological reaction against the materialnor are toxic, but which do not degrade within the body over time. Inanother embodiment, the scaffold component 422 is formed ofbiocompatible materials, i.e., materials which do not elicit a strongimmunological reaction against the material nor are toxic, and whichdegrade into non-toxic, non-immunogenic chemical species which areremoved from the body by excretion or metabolism. In yet anotherembodiment, the scaffold component 422 is formed of biodegradablematerials, i.e., materials which are enzymatically or chemicallydegraded in vivo into simpler chemical species.

In some embodiments, the scaffold component 422 is made of biocompatibleand/or biodegradable materials. Thus, the scaffold component 422 mayremain at the site of the defect 104 even if the bladder 105 is removedfrom the knee joint. When the scaffold component 422 remains in the kneejoint, it should be constructed of materials having appropriatedimensions for the site and sufficient strength to support new tissuegrowth. The biocompatible and/or biodegradable materials may include,but is not limited to, lactide, poly(lactide) (PLA), glycolide polymers,poly(glycolic acid) (PGA), poly(lactide-co-glycolide) (PLGA), ethyleneglycol/lactide copolymers, polycaprolactone, poly (p-dioxanone),polyhydroxybutyrate, polyurethanes, polyphosphazenes, poly(ethyleneglycol)-poly(lactide-co-glycolide) co-polymer, polyhydroxyacids,polycarbonates, polyamides, polyanhydrides, polyamino acids, polyorthoesters, polyacetals, degradable polycyanoacrylates, polycarbonates,polyfumarates, degradable polyurethanes, proteins such as albumin,collagen, fibrin, synthetic and natural polyamino acids, polysaccharidessuch as alginate, heparin, other naturally occurring biodegradablepolymers of sugar units, processed cadaveric or non-human tissuesincluding but not limited to dermis, pericardium, tendon, or cartilage.

If the scaffold component 422 is made of biocompatible and/orbiodegradable materials, the materials may be designed to degrade withina desired time frame. In one embodiment, the desired degradation timeframe is one to two weeks. In another embodiment, the desireddegradation time frame is between one month and one year. In yet anotherembodiment, the desired degradation time is greater than a year.Further, in some embodiments, scaffold component 422 made ofbiocompatible or biodegradable materials may degrade in a manner relatedto the molecular weights of the materials used to make the scaffoldcomponent 422. Thus, a higher molecular weight material may result inscaffold component 422 that retains its structural integrity for longerperiods of time, while lower molecular weights result in fasterdegradation with shorter scaffold life.

As indicated above, the cavity 130 may include a material positionedwithin the void adjacent the defect 104 that promotes healing of thedefect 104, provides additional structural support, and provides abarrier to isolate the reduced-pressure chamber 106 from the defect 104.FIG. 5 illustrates another embodiment of the reduced-pressure chamber106 comprising a barrier material 520 that covers the opening in theexterior wall 126 and closes the cavity 130. The barrier material 520may be attached to the manifold structure 120 and/or attached to theexterior wall 126 of the reduced-pressure chamber 106. Thus, the barriermaterial 520 directly contacts the surface of the defect 104 when thecavity 130 is placed adjacent the defect 104.

The barrier material 520 may comprise one or more pieces of materialthat covers a portion, or all, of the exterior wall 126 of thereduced-pressure chamber 106. The barrier material 520 is preferablyfabricated from a material that allows the reduced-pressure chamber 106to be in fluid communication with the defect 104 while isolating thedefect 104 from direct communication with the cavity 130. As such, thebarrier material 520 may be, for example, a mesh, sieve, a screen, or asolid sheet with spaces or a punched pattern. The barrier material 520may have sufficient strength to provide additional structural supportfor the knee joint.

Referring to FIG. 6, the reduced pressure therapy system 100 may furthercomprise pressure sensors 140, 142 operably connected to the first andsecond conduits 110, 112 to measure the reduced pressure and the bracingpressure, respectively. The system further includes a control unit 145electrically connected to the pressure sensors 140, 142, the reducedpressure source 115, and the first fluid supply 111 that provides thebracing fluids through the second conduit 112 to the bracing chamber107. The pressure sensor 140 measures the reduced pressure of thereduced-pressure chamber 106, and also may indicate whether the firstconduit 110 is occluded with blood or other bodily fluids. The pressuresensor 140 also provides feedback to control unit 145 which regulatesthe reduced-pressure therapy being applied by the reduced-pressuresource 115 through the first conduit 110 to the reduced-pressure chamber106. Correspondingly, the pressure sensor 142 measures the positivepressure of the bracing fluid being applied by the first fluid supply111 through the second conduit 112 to the bracing chamber 107. Thepressure sensor 142 also provides feedback to the control unit 145 whichregulates positive pressure therapy being applied by thereduced-pressure source 115 to the bracing chamber 107. The control unit145 also balances the relative amount of reduced pressure and positivepressure being applied to the reduced-pressure chamber 106 and thebracing chamber 107, respectively, so that sufficient pressures arebeing applied to both the femur 102 and the tibia 103, respectively, andthe interior wall 108 as described above.

The reduced-pressure therapy system 100 may also comprise a second fluidsupply 150 fluidly coupled to the first conduit 110 via third conduit152 and operatively connected to the control unit 145. The second fluidsupply 150 may be used to deliver growth and/or healing agents to thedefect 104 including, without limitation, an antibacterial agent, anantiviral agent, a cell-growth promotion agent, an irrigation fluid, orother chemically active agents. The system 100 further comprises a firstvalve 154 positioned in the third conduit 152 to control the flow offluid therethrough, and a second valve 156 positioned in the firstconduit 110 between the reduced-pressure source 115 and the juncturebetween the first conduit 110 and the third conduit 152 to control theflow of reduced pressure. The control unit 145 is electrically connectedto the second fluid supply 150 and the first and second valves 154, 156to control the delivery of reduced pressure and/or fluid from the secondfluid supply 150 to the reduced-pressure chamber 106 as required by theparticular therapy being administered to the patient. The second fluidsupply 150 may deliver the liquids as indicated above, but may alsodeliver air to the reduced-pressure chamber 106 to promote healing andfacilitate drainage at the site of the defect 104.

The independent paths of fluid communication provided by the conduits110, 112, and 152 may be accomplished in a number of different ways,including that of providing a single, multi-lumen tube with two or morelumens. A person of ordinary skill in the art will recognize that thepressure sensors 140, 142, valves 154, 156, and other componentsassociated with the conduits could also be similarly associated with aparticular lumen in the delivery tube if a multi-lumen tube is used.Further, additional lumens may be provided to separately introduce airor other fluids to the site of the defect 104, including, withoutlimitation, an antibacterial agent, an antiviral agent, a cell-growthpromotion agent, an irrigation fluid, or other chemically active agents.

Referring to FIGS. 7A and 2C, the exterior walls 126, 127 of the bladder105 are flexible as described above. Thus, the bladder 105 may becollapsed or flattened as shown more specifically in FIG. 2C as aflattened bladder 205 and preferably flattened at the edge where theinterior wall 108 intersects the exterior walls 126, 127, the edges ofwhich are indicated by the reference number 708 shown by the dashed linein FIG. 7A. The flattened bladder 205 is then folded or rolled as shownin FIG. 7B into a substantially tubular shape as indicated by referencenumeral 705. It should be understood again as described above that thereduced-pressure chamber 106 and the bracing chamber 107 (not shown) maynot share a common wall such as the interior wall 108, but may haveseparate walls. The rolled bladder 705 along with the first and secondconduits 110, 112 may then be inserted into a delivery catheter 710 asshown in FIG. 7C. The delivery catheter 710 has a distal end 712 thattapers so that the delivery catheter 710 may be surgically orpercutaneously inserted in the knee joint between the femur 102 and thetibia 103 to deliver the rolled bladder 705 to the desired lateral siteadjacent the defect 104 as shown in FIG. 8. When percutaneouslyinserted, the delivery catheter 710 may be inserted through a sterileinsertion sheath (not shown) that penetrates the skin tissue of thepatient. The distal end 712 of the delivery catheter 710 is tapered toassist movement of the delivery catheter 710 through the tissues of theknee joint, but must also have a sufficiently large opening in thetapered distal end 712 to allow the rolled bladder 705 to be pushed outof the delivery catheter 710 and inserted into the knee joint of thepatient.

The delivery catheter 710 may be made of any material that providessufficient strength to allow the delivery catheter 710 to be pushedthrough the bodily tissues into the knee joint of the patient.Preferably, the materials of the delivery catheter 710 should bebioinert, therefore not causing injury, toxic or immunologic reaction tothe surrounding body tissues. Materials of interest includes, but arenot limited to, polyimide, polyamide, PBAX™, polyethylene,fluoropolymer, polyurethane, polyisoprene, nylon, steel and the like. Itis also contemplated that in one alternate embodiment, the materials ofthe delivery catheter 710 will allow the delivery catheter 710 an amountof flex. Further, in one embodiment, outer diameter of the deliverycatheter 710 is coated with agents to prevent the tube from adhering tothe body tissues. For example, the tubing may be coated with heparin,anticoagulants, anti-fibrogens, anti-adherents, anti-thrombinogens orhydrophilic substances. In another embodiment, the outer diameter and/orinterior diameter of the delivery catheter 710 are coated with alubricant agent, including but not limited to, silicone, hydrophiliccoating, Surmodics® lubricants, and the like.

Referring again to FIG. 8, the distal end 712 of the delivery catheter710 is pushed through the skin 702 of the leg 101 of the patient untilit is positioned adjacent the knee joint. The first and second conduits110 and 112, collectively referred to as the conduits 719, may then bemanually pushed to force the rolled bladder 705 through the deliverycatheter 710 and out of the distal end 712 of the delivery catheter 710until the rolled bladder 705 is laterally positioned at the desired siteadjacent the defect 104. As described above, the femur 102 with thedefect 104 may have already undergone microfracture surgery. Although itis understood that exact equipment and method of microfracture surgerymay change over time, one of skill in the art readily understands theprocedure of microfracture surgery generally includes the medicalpractitioner, i.e., surgeon or nurse practitioner, who cuts a smallincision on the skin 702 exterior to the knee joint. A long thin scope(not shown), for example, an arthroscope, may be inserted through theskin 702 and through the body tissues 703 to the site of the defect 104.If necessary, calcified cartilage is removed. The surgeon may thencreate microfractures, i.e., small holes, scrapes, tears, in the femur102 near the defective cartilage, i.e., the defect 104. After the longthin scope is removed, the delivery catheter 710 may be inserted throughthe same skin opening 702 and body tissue 703 path formed by the scope.In another embodiment, a separate, additional skin opening may be formedfor receiving the delivery catheter 710. After the distal end 712 of thedelivery catheter 710 is delivered to the surgical site, the conduits719 may be mechanically or manually pushed so that the rolled bladder705 moves through and out the distal end 712 of the delivery catheter710 to be positioned at the desired site adjacent the defect 104.

After the rolled bladder 705 reaches the desired lateral positionadjacent the defect 104, the delivery catheter 710 may be removed fromthe patient's leg 101. The rolled bladder 705 may then be unrolled inthe opposite direction shown in FIG.7B to a relatively flattened shapewith the cavity 130 positioned adjacent the defect 104. When the firstand second conduits 110, 112 are reconnected to the reduced pressuresource 115 and the first fluid supply 111, a positive pressure isapplied by the bracing fluid to the bracing chamber 107 so that itexpands and exerts a force on the tibia 103 and on the interior wall 108as described above while at the same time applying a reduced pressure tothe reduced-pressure chamber 106 so that the opening 128 in thereduced-pressure chamber 106 (see FIG. 2B) substantially seals thedefect 104 as shown in FIG. 1A and described in detail above. Thepositive pressure applied to the bracing chamber 107 and the weight ofthe patient being applied by the femur 102 through the manifoldstructure 120 and the interior wall 108 cause the exterior wall 127 ofthe bracing chamber 107 to mold to the curvature of the tibia 103 andthe surrounding body tissues. Application of the positive pressure tothe bracing chamber 107 also forces the interior wall 108 and themanifold structure 120 against the distal end of the femur to force theopening 128 of the reduced-pressure chamber 106 against the defect 104after which a reduced pressure is applied to the defect 104 via thecavity 130.

As described and shown in FIGS. 1A, 4, and 5 above, the cavity 130 maybe filled with the scaffold component 422 or covered by a barriermaterial 520 closing the opening of the cavity 130. Regardless of thestructure, a reduced pressure is ultimately applied via the opening 128in the reduced-pressure chamber 106 to the defect 104 so that thereduced pressure increases the seepage of blood and bone marrow throughthe fractures created by the microfracturing surgery to draw blood andother stimulatory agents to the defect site. The reduced pressuretherapy or treatment applied to the defect 104 depends on the size andshape of the defect 104 and various other factors known in the art.Consequently, the reduced pressure being applied may be continuous,variable at a specific frequency, or generally cyclical over timedepending on the desired treatment for the patient and thecharacteristics of the defect 104. The opening 128 in thereduced-pressure chamber 106 not only applies the reduced pressuredirectly to the defect 104, but also mitigates the removal of thesinovial fluid from the knee joint while the reduced pressure is beingapplied to the defect 104.

Referring to FIG. 9, another embodiment of a bladder 905 is shown thatis substantially similar to the bladder 105 described above includingthe same components identified with similar reference numerals. Thebladder 905 comprises a reduced-pressure chamber 906 and a bracingchamber 907 separated by an interior wall 908, each chamber having anexterior wall 926 and 927, respectively, all as described above withrespect to the bladder 105. The reduced-pressure chamber 906 alsoincludes a manifold structure 920 that functions in the same fashion asthe manifold structure 420 described above that fills most of thereduced-pressure chamber 906. The reduced-pressure chamber 906 and thebracing chamber 907 each comprise an elongated conduit 914 and 916,respectively, fluidly coupled to each chamber and extending from thebladder 905 through the skin of the leg 101 of the patient. Theelongated conduits 914, 916 may be an integrated portion of thereduced-pressure exterior wall 126 and the bracing exterior wall 127,respectively, with the interior wall 908 extending therebetween. Themanifold structure 920 extends through and substantially fills theelongated conduit 914 of the reduced-pressure chamber 906. The distalends of the elongated conduit 914, 916 may be fluidly coupled to thefirst conduit 110 and the second conduit 112, respectively, forproviding a reduced pressure to the reduced-pressure chamber 906 andbracing fluid under a positive pressure to the bracing chamber 907 whichfunction in the same manner as described above. The portion of themanifold structure 920 extending through the elongated conduit 914 ofthe reduced-pressure chamber 906 provides additional structural supportfor the reduced pressure chamber 906 so that the bladder 905 can be moreeasily flattened or rolled as described above to facilitate insertion ofthe bladder 905 into the delivery catheter 710 (not shown).

Referring to FIG. 10A, a perspective view of the bladder 105 and thefirst and second conduits 110, 112 is shown. The bladder 105 furthercomprises an elongated tab 109 extending from the end of the bladder 105opposite the side that is fluidly coupled to the first and secondconduits 110, 112 (see also FIG. 1A). The elongated tab 109 is usefulfor guiding and manipulating the bladder 105 to the desired lateralposition adjacent the defect 104 as described above. More specifically,the arthroscope may be inserted completely through the knee joint tocreate a path for the elongated tab 109 which would be inserted inadvance of the bladder 105 through the delivery catheter 710 andultimately extend out the other side of the patient's leg 101 as shownin FIG. 1A. The elongated tab 109 may be affixed to the exterior wall126 of the reduced-pressure chamber 106 to facilitate positioning of theopening 128 in the reduced-pressure chamber 106 adjacent the defect 104.The elongated tab 109 may be affixed to the bladder 105 either prior tobeing inserted into the knee joint, or at any later point during thesurgery to facilitate positioning of the bladder 105. For example, theelongated tab may be inserted from the opposite side of the knee jointthrough the incisional pathway and into the distal end 712 of thedelivery catheter 710 where it can be affixed to or screwed into thebladder 105. The elongated tab 109 then can be used to pull the bladder105 through the delivery catheter 710 instead of using the first andsecond conduits 110, 112 to push the bladder 105 to the desiredposition.

The bladder 105 may also include a sheath 119 covering the first andsecond conduits 110, 112 and affixed directly to the bladder 105. Thesheath 119 may be constructed of a material for providing additionalstrength to the first and second conduits 110, 112 for pushing thebladder 105 into the desired position adjacent the defect 104 asdescribed above. The sheath 119 and the elongated tab 109 may also be asingle continuous piece of material as shown in FIG. 10B to furtherfacilitate pushing and/or pulling the bladder 105 to the desired lateralposition adjacent the defect 104 and positioning the opening 128 in thereduced-pressure chamber 106 so that it fully contacts the defect 104.

The design and materials of the bladder chamber, delivery tubes, and thelike may be any contemplated in other embodiments of the application andare dependent upon numerous factors, including, for example, thelocation and size of the tissue site, the pressure of the bracingchamber to maintain the position of the opening 128 in thereduced-pressure chamber 106 against the defect 104. It is contemplatedfurther that for all of the embodiments described herein, the number,size and type of bladder chambers may vary, depending upon the shape ofthe bone that contains the one or more tissue sites. As such, to betterexpand the bracing chambers and seal the one or more supportive foamstructures to the bone comprising the tissue site, the bladder chambermay have two or more bracing chambers.

The application is also directed to a method of administering a reducedpressure therapy to a tissue site as described above, but more generallyaccording to the following steps. The method comprises performingmicrofracture surgery on a bone at a tissue site and then delivering anembodiment of the reduced pressure delivery system described above tothe tissue site. The method then comprises delivering a bracingsubstance to the bracing chamber such that the tissue site contactsurface is in contact with the tissue site and delivering a reducedpressure to the reduced pressure chamber causing reduced pressure to beapplied to the tissue site. This method can be used on any tissue sitethat is subjected to microfracture surgery. In some embodiments, thetissue site may be located in the knee joint as described above.

In additional embodiments, the application is directed to a method ofperforming microfracture surgery to a knee. The method comprisescreating at least one microfracture in a bone at the base of anarticular cartilage defect in the knee, then applying reduced pressureto the site of the defect. The reduced pressure in these embodiments canbe applied by any means known in the art, and through any known systemcapable of delivering reduced pressure to the site. In some embodiments,the reduced pressure is applied using any appropriate embodiment of thereduced pressure delivery system described above.

As various changes could be made in any of the systems, apparatuses andmethods described above without departing from the scope of theinventions, it is intended that all matter contained in the abovedescription and shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

All references cited in this specification are hereby incorporated byreference. The discussion of the references herein is intended merely tosummarize the assertions made by the applicants and no admission is madethat any reference constitutes prior art. Applicants reserve the rightto challenge the accuracy and pertinence of the cited references.

We claim:
 1. A bladder for applying a treatment to a defect in a firstbone or a second bone of two bones forming a joint, the bladdercomprising: a reduced-pressure bladder having an exterior wall forming areduced-pressure chamber with an interior surface, an opening to thereduced-pressure chamber adapted to substantially surround the defectwhen positioned against the first bone, and a reduced-pressure port influid communication with the reduced pressure chamber for receivingreduced pressure from a source of reduced pressure; a manifold disposedwithin the reduced-pressure chamber and having a surface adapted to forma cavity with a portion of the interior surface when reduced pressure isprovided to the reduced-pressure chamber and also providing structuralsupport between the interior surface and the exterior wall to preventthe cavity from collapsing, wherein the reduced-pressure bladder sealsthe opening around the defect that closes the cavity and is therebyexposed to the reduced pressure within the cavity; and a bracing bladderhaving an exterior wall forming a bracing chamber for receiving a fluid,a first surface of the exterior wall affixed to the reduced-pressurebladder opposite the opening, a second surface of the exterior wallopposing the first surface adapted to be positioned against the secondbone, and a port for providing the fluid to the bracing chamber under apositive pressure, the bracing bladder being inflatable with the fluidto provide a cushion between the reduced-pressure bladder and the secondbone when the positive pressure is provided to the bracing chamber. 2.The bladder of claim 1, wherein the manifold substantially fills thereduced-pressure chamber and includes a surface exposed through theopening for being positioned adjacent the defect.
 3. The bladder ofclaim 2, wherein the manifold is a foam material in fluid communicationwith the defect.
 4. The bladder of claim 3, wherein the foam materialcomprises a plurality of open cells having a size ranging from about 100microns to about 1,500 microns.
 5. The bladder of claim 2, wherein thefirst surface of the bracing bladder forms a common wall between thebracing bladder and the reduced-pressure bladder.
 6. The bladder ofclaim 5, wherein the common wall is substantially inflexible.
 7. Thebladder of claim 2, wherein the manifold further comprises a scaffoldcomponent sized to fill the defect to facilitate tissue formation in thedefect.
 8. The bladder of claim 7, wherein the scaffold componentprovides additional support between the first bone and the bracingbladder.
 9. The bladder of claim 7, wherein the scaffold component isbioabsorbable.
 10. The bladder of claim 9, wherein the scaffoldcomponent adheres to the defect.
 11. The bladder of claim 7, wherein thescaffold component is coated or infused with growth factors ornutrients.
 12. The bladder of claim 1, wherein the reduced pressurebladder and the bracing bladder are comprised of one or more elastomers.13. The bladder of claim 1, wherein the manifold partially fills thereduced-pressure chamber.
 14. The bladder of claim 13, wherein the firstsurface of the bracing bladder forms a common wall between the bracingbladder and the reduced-pressure bladder.
 15. The bladder of claim 14,wherein the common wall is substantially rigid.
 16. The bladder of claim13, further comprising a foam structure positioned in the cavity toprovide additional support between the first bone and the bracingbladder.
 17. The bladder of claim 16, wherein the foam structure isbioabsorbable.
 18. The bladder of claim 16, wherein the foam structureserves as a scaffold for tissue growth.
 19. The bladder of claim 18,wherein the foam structure is coated or infused with growth factors ornutrients.
 20. The bladder of claim 16, wherein the foam structureadheres to the defect.
 21. The bladder of claim 1, further comprising abarrier material covering the opening and closing the cavity, andadapted to directly contact the defect when the reduced-pressure bladderis positioned against the first bone.
 22. A bladder for applying atreatment to a defect in a first bone or a second bone of two bonesforming a joint, the bladder comprising: a reduced-pressure bladderhaving a reduced-pressure port for fluid communication with a source ofreduced pressure and an opening sized to substantially surround thedefect in the first bone; a bracing bladder having a positive-pressureport for receiving a fluid under a positive pressure and being affixedto the reduced-pressure bladder; a manifold disposed within thereduced-pressure bladder and having a surface adapted to form a cavityadjacent the opening for distributing reduced pressure to the defect andproviding structural support between the first bone and the bracingbladder to prevent the cavity from collapsing when reduced pressure isprovided to the reduced-pressure bladder; and wherein the bracingbladder inflates with the fluid when positive pressure is applied to thepositive-pressure port to provide a cushion between the manifold and thesecond bone, and wherein the reduced-pressure bladder seals the openingaround the defect that closes the cavity and is thereby exposed to thereduced pressure within the cavity when reduced pressure is provided tothe reduced-pressure bladder.
 23. The bladder of claim 22, wherein themanifold substantially fills the reduced-pressure bladder and covers theopening in the reduced-pressure bladder whereby the manifold distributesreduced pressure directly to the defect via the opening.
 24. The bladderof claim 23, wherein the manifold is a foam material in fluidcommunication with the defect.
 25. The bladder of claim 24, wherein thefoam material comprises a plurality of open cells have a size rangingfrom about 100 microns to about 1,500 microns.
 26. The bladder of claim23, further comprising a common wall between the bracing bladder and thereduced-pressure.
 27. The bladder of claim 26, wherein the common wallis substantially inflexible.
 28. The bladder of claim 23, wherein themanifold further comprises a scaffold component sized to fill the defectto facilitate tissue formation.
 29. The bladder of claim 28, wherein thescaffold component provides additional support between the first boneand the bracing bladder.
 30. The bladder of claim 28, wherein thescaffold component is bioabsorbable.
 31. The bladder of claim 30,wherein the scaffold component adheres to the defect.
 32. The bladder ofclaim 30, wherein the scaffold component adheres to the manifold. 33.The bladder of claim 28, wherein the scaffold component is coated orinfused with growth factors or nutrients.
 34. The bladder of claim 22,wherein the reduced pressure bladder and the bracing bladder arecomprised of one or more elastomers.
 35. The bladder of claim 22,wherein the manifold partially fills the reduced-pressure bladdercontacting a portion of the reduced-pressure bladder.
 36. The bladder ofclaim 35, wherein the manifold is a foam material in fluid communicationwith the defect.
 37. The bladder of claim 36, wherein the foam materialcomprises a plurality of open cells have a size ranging from about 100microns to about 1,500 microns.
 38. The bladder of claim 35, wherein themanifold further comprises a scaffold component sized to fill the defectto facilitate new tissue formation.
 39. The bladder of claim 35, furthercomprising a common wall between the bracing bladder and thereduced-pressure.
 40. The bladder of claim 39, wherein the common wallis substantially rigid.
 41. The bladder of claim 35, further comprisinga foam structure positioned in the cavity to provide additional supportbetween the first bone and the bracing bladder.
 42. The bladder of claim41, wherein the foam structure is bioabsorbable.
 43. The bladder ofclaim 41, wherein the foam structure serves as a scaffold for tissuegrowth.
 44. The bladder of claim 41, wherein the foam material is coatedor infused with growth factors or nutrients.
 45. The bladder of claim41, wherein the foam structure adheres to the manifold.
 46. The bladderof claim 22, further comprising a barrier material covering the openingand closing the cavity, and adapted to directly contact the defect whenthe reduced-pressure bladder is positioned against the first bone.